Chemistry Commons^™

Optical Measurement And Performance Prediction Of Solar Pv System In Al-Khidhir Zone/Iraq, Faten Sh. Zainulabdeen, Jaber O. Dahloos, Ahmed F. Atwan, Naseer K. Kasim

Karbala International Journal of Modern Science

People have tended for investing the sources of renewable energy, especially solar energy, as they are clean and environmentally friendly sources. The present work aims to invest the measured data of solar irradiance, maximum ambient temperatures and wind speed provided by Al Khidhir Meteorological Station to predict the minimum performance of photovoltaic solar systems (NT-R0E3E-SHARP) for electric power generation. The single diode model is used to calculate the minimum output power produced by solar module and its minimum conversion efficiency based on soalr irradiance, maximum ambient temperatures and wind speed throughout 2020. The results indicate that the annual solar irradiance …

Probing Convergence In Orthogonal Conjugated Catalysis By T4 Lysozyme Utilizing Biophysical Characterization, William Turner

Master of Science in Chemical Sciences Theses

Conjugated polymers have become highly attractive as they afford unique material properties that make them promising for a wide range of applications, such as photovoltaics and drug delivery systems. However, these conjugated polymers require extensive synthetic steps involving hazardous organic solvents or metal-based catalysts yielding toxic waste streams. To remedy this, enzymes have emerged as a highly valuable alternative to synthesizing these polymers as they are able to be produced in environmentally benign conditions and have played a pivotal role in various biosynthetic strategies in recent years. Serving as model systems, lysozymes have been shown to polymerize 2-ethynylpyridine (2-EP) via …

Determining The Structure And Activity Of A Pseudomonas Aeruginosa Protein, Ivyp2, Katherine Letsinger

Master of Science in Chemical Sciences Theses

Various biophysical methods were employed to structurally characterize and assess the activity of an important resistance factor (Ivyp2) from the multi-drug resistant Gram-negative bacterium Pseudomonas aeruginosa. This opportunistic pathogen accounts for approximately 10% of all hospital-acquired infections in the United States and contains a number of virulence factors that aid in its ability to infect and colonize immunocompromised individuals and those with cystic fibrosis. One of these factors – inhibitor of vertebrate lysozyme, or Ivy – neutralizes the lytic activity of lysozyme, an antimicrobial enzyme part of the innate immune system that hydrolyzes the linkages between bacterial cell wall subunits. …

Simple Arenes As Aryne Synthetic Equivalents Via Sulfonium Salt Intermediates, Riley A. Roberts

Student Research Symposium

Arynes are ephemeral molecules that are yet to be fully exploited in synthetic strategy because they are often challenging to access. These reactive intermediates participate in a myriad of reactions that conventional chemistry is incapable of, making them extremely useful for the synthesis of important molecules like pharmaceuticals and agrochemicals. While classical approaches for synthesizing arynes employ cheap starting material, extremely harsh reagents are necessary to generate the aryne. In contrast, methods that do not require harsh reaction conditions do require starting material that is exceedingly difficult to synthesize. To access arynes quickly and efficiently, the work described herein aims …

Comparison Of Heavy Metals In Spinach Grown On The Roof Ground Location At Portland State University, Tyler A. Robin

Student Research Symposium

As a result of urbanization, fresh, healthy food can be expensive and easily contaminated but space for local farming is limited. Roofs can be underutilized in densely populated cities and can offer a space for local fresh farming. The purpose of this study is to continue a previous study done in 2021, to find if growing leafy vegetables on the roof can limit heavy metal exposure from air pollutants. This study compares spinach grown on the roof in 2021, 2019 and spinach bought from stores around the Portland State University campus and the heavy metals found in these greens. The …

Computational Investigation Of The Mechanism Of An Octahedral Ni(Ii) Proton Reduction Catalyst And Importance Of Intramolecular Hydrogen Bonding, Avik Bhattacharjee, Dayalis S.V. Brown, Carolyn N. Virca, Trent E. Ethridge, Oreana Mendez Galue, Uyen T. Pham, Theresa M. Mccormick

Student Research Symposium

Water-splitting to make hydrogen gas is of extreme importance in the field of alternative energy research. Transition-metal complexes are capable of catalyzing the conversion of water to hydrogen at higher pH, with low overpotential. Our research focuses on the importance of intramolecular hydrogen bonding (H-bonding) on the pKa and thermodynamic stability of the catalytic intermediates of a well-known proton-reduction catalyst, nickel (II) tris-pyridinethiolate. Density Functional Theory (DFT) calculations on the parent catalyst and eleven derivatives demonstrate geometric isomer formation after the protonation step of catalysis. These isomers differ in the relative thermodynamic stabilities and pKa values, which can be attributed …

Stabilization Of Phenanthrene Anions In Helium Nanodroplets, Siegfried Kollotzek, Farhad Izadi, Miriam Meyer, Stefan Bergmeister, Fabio Zappa, Stephan Denifl, Olof E. Echt, Paul Scheier, Elisabeth Gruber

Faculty Publications

It has been debated for years if the polycyclic aromatic hydrocarbon phenanthrene exists in its anionic form, or, in other words, if its electron affinity (EA) is positive or negative. In this contribution we confirm that the bare phenanthrene anion Ph^- created in a binary collision with an electron at room temperature has a lifetime shorter than microseconds. However, the embedding of neutral phenanthrene molecules in negatively charged helium nanodroplets enables the formation of phenanthrene anions by charge transfer processes and the stabilization of the latter in the ultracold environment. Gentle shrinking of the helium matrix of phenanthrene-doped HNDs …

Unusual High-Frequency Mechanical Properties Of Polymer-Grafted Nanoparticle Melts, Mayank Jhalaria, Yu Chang, Yucheng Huang, Brian C. Benicewicz, Sanat K. Kumar, George Fytas

Faculty Publications

Brillouin light spectroscopy is used to measure the elastic moduli of spherical polymer-grafted nanoparticle (GNP) melts as a function of chain length at fixed grafting density (0.47  chains/nm²) and nanoparticle radius (8 nm). While the moduli follow a rule of mixtures (Wood’s law) for long chains, they display enhanced elasticity and anomalous dissipation for graft chains <1⁢0⁢0  kDa. GNP melts with long polymers at high 𝜎 have a dry zone near the GNP core, surrounded by a region where the grafts can interpenetrate with chain fragments from adjacent GNPs. We propose that the departures from Wood’s law for short chains are due to the effectively larger silica volume fraction in the region where sound propagates—this is caused by the short, interpenetrated chain fragments being pushed out of the way. We thus conclude that transport mechanisms (of gas, ions, sound, thermal phonons) in GNP melts are radically different if interpenetrated chain segments can be “pushed out of the way” or not. This provides a facile new means for manipulating the properties of these materials.

Computational And Spectroscopic Studies Of New Sulfur-Containing Dipole-Bound Anions, Nicholas Allen Kruse

Honors Theses

Sulfur and Nitrogen are essential ingredients in both life-supporting and light-harvesting molecules. Their presence also usually leads to the delocalization of electrons and large dipole and quadrupole moments. Such molecules are sometimes able to form negative ions through the electrostatic binding of an excess electron. These so-called multipole-bound (dipole-bound, quadrupole-bound, etc.) anions have been shown to be important in radiation damage in biology and electron transport processes. Here, we present our recent computational and experimental results studying the creation of new multipole-bound anions.

The Design Of A Pcr-Based Assay To Detect And Isolate The Serine Palmitolytransferase Gene From Environmental Bacteria, Lana Taylor

Honors Theses

Sphingolipids are a natural class of lipids that function as structural elements of cell membranes and signaling molecules for important cellular activities such as cell growth, differentiation, apoptosis, recognition, and adhesion. These lipids can be found universally in eukaryotic cells as well as some species of bacteria, such as those found in the human gut microbiome and in the environment in soils. Though sphingolipid production is rare in bacteria, both eukaryotic and prokaryotic sphingolipid biosynthesis begin with the condensation of serine and palmitoyl CoA into 3-ketodihydrosphingosine catalyzed by the enzyme serine palmitoyltransferase (SPT). In recent years, several studies have shown …

Covalent Modification Of Recombinant Protein With Reactive Thiols, Sawyer Dulaney, Bailey Taylor

Honors Theses

Many diseases cause chronic and painful inflammation in different body systems. One of the front-line drug classes to treat such inflammation is Nonsteroidal Anti-Inflammatory Drugs (NSAIDs). Despite the benefits of oral administration of NSAIDs, there are drawbacks to their long-term usage because they can cause detrimental effects on off-target systems in the body such as the liver, kidney, or the lining of the intestinal tract. An alternative to NSAIDs is the usage of hydrogels for targeted drug delivery. Hydrogels can provide drug delivery in a specific portion of the site of inflammation, thus allowing higher doses of medication to be …

Development Of An Analytical Method For Determination Of Lead And Cadmium In Biological Materials By Gfaas Using Escherichia Coli As Model Substance, Michelle Catherine Gende, Martina Schmeling

Chemistry: Faculty Publications and Other Works

In this work, an analytical method was developed for the determination of lead and cadmium in biological samples using graphite furnace atomic absorption spectrometry. Escherichia coli (E. coli) was chosen as model substance for this purpose as it is readily available in most laboratories and can be quickly and easily prepared with a high turnaround rate. Four different sample preparation methods were initially evaluated with respect to percent recovery, limit of detection, and limit of quantification, and the most promising one was developed further. The final process involving microwave assisted digestion of the sample with nitric acid …

Aloso: Spectroscopy And Structure Of A New Group Of Astrochemical Molecules, Vincent J. Esposito, Tarek Trabelsi, Joseph S. Francisco

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

No abstract provided.

High Performance Liquid Chromatography Monitoring Reaction Kinetics, Ken Overway, Mary Ruth Shifflett

Chemistry Faculty Scholarship

To develop a chromatographic method to characterize enantioselective kinetics, the reaction between aromatic aldehydes and ephedrine will be monitored with High Performance Liquid Chromatography (HPLC). First, develop kinetics analysis procedure with the HPLC, the decomposition of aspartame was observed with citrate and phosphate buffers. The procedure produced an activation energy in the presence of phosphate buffer of 71.9 kJ/mol with a -0.126 % error. The aromatic aldehyde, benzaldehyde, and ephedrine were run through a stereospecific column to separate peaks with various mobile phases. A more nonpolar mobile phase is required for better peak and retention time separation.

Drug Loaded Mesoporous Nanocarriers For The Detection Of Aspergillosis, Madeline Jewel Brooks

Honors Capstone Projects and Theses

No abstract provided.

Spectral Signatures Of Hydrogen Thioperoxide (Hosh) And Hydrogen Persulfide (Hssh): Possible Molecular Sulfur Sinks In The Dense Ism, Charles Z. Palmer, Ryan C. Fortenberry, Joseph S. Francisco

Faculty and Student Publications

For decades, sulfur has remained underdetected in molecular form within the dense interstellar medium (ISM), and somewhere a molecular sulfur sink exists where it may be hiding. With the discovery of hydrogen peroxide (HOOH) in the ISM in 2011, a natural starting point may be found in sulfur-bearing analogs that are chemically similar to HOOH: hydrogen thioperoxide (HOSH) and hydrogen persulfide (HSSH). The present theoretical study couples the accuracy in the anharmonic fundamental vibrational frequencies from the explicitly correlated coupled cluster theory with the accurate rotational constants provided by canonical high-level coupled cluster theory to produce rovibrational spectra for use …

Understanding Biogeochemical And Physical Controls On Methane Air-Sea Exchange Fluxes In The Pacific Ocean, Sarah Raney

Master's Theses

Methane and trace element samples were collected on GEOTRACES GP15 Pacific Meridional Transect (PMT) cruise conducted between the Aleutian Islands (57 °N) and Tahiti (20 °S) from September to November 2018. Uncertainty in methane air-sea exchange fluxes was determined using a propagation of errors approach. Fluxes ranged from -0.88 to 4.9 µmol CH₄ m^-2 d^-1. Average CH₄ flux along the Alaskan margin was 2.2 ± 2.9 µmol CH₄ m^-2 d^-1. Methane fluxes decreased moving southward and increased to their open ocean maximum around 20 °N before declining in equatorial waters. Near …

Real-Time Monitoring Of Paraquat Photodegradation Using Colloidal Gold Surface Enhanced Raman Spectroscopy, Nathan Wilson

Masters Theses & Specialist Projects

Monitoring chemical reactions in aqueous solution is a challenge because most instrumental techniques either are not suited for the rapid timescales, are not sensitive enough to detect products at low concentrations, or do not have sufficient structure-to-spectrum relationships. Raman spectroscopy is a promising method to monitor reactions, as it is fast, dependent on chemical structure, and has little interference from water. However, Raman scattering is generally very weak. Surface-enhanced Raman spectroscopy (SERS) improves the signal strength of Raman spectroscopy by using a metal surface plasmon, or oscillation of the surface’s electrons, to allow for highly selective and sensitive detection and …

Stem Club, Camden Jones, Erica Gesner, Amber Gadeken

Honors Program: Expanded Learning Clubs

The goal of this club is to introduce various topics stemming from different fields in science. We hope to excite the students about science and show them how important it is to their everyday lives. This club also aims to provide free education to underserved communities.

Towards The Determination Of Estrone And 17Β-Estradiol In Dairy Cattle Waste Using Solid Phase And Stir Bar Sorptive Extractions With Liquid Chromatography-Mass Spectrometry And Gas Chromatography-Mass Spectrometry, Pallavi Ragi

Masters Theses & Specialist Projects

Steroidal hormones are naturally produced as a part of many physiological processes and are excreted in the urine and feces of animals and humans. Farm animals in concentrated animal feeding operations (CAFOs) are routinely implanted with synthetic and natural hormones to enhance growth and production, contributing significantly to environmental steroid hormone contamination. Every year around 49 tons of estrogens are generated by livestock waste in the United States alone. Due to rainfall and runoff, these steroid hormones reach the environment when animal waste is applied as manure. Studies show that estrogens and other steroidal hormones present in the surface waters …

Dynamics Of Chemical Reaction Networks, Igor Vouffo

Honor’s College Freeman Research Journal

Network architecture imposes constrains on the types of dynamics a network system admits. Chemical reaction networks have further constrains coming from a special feature of reaction rate functions: the kinetic equations can be written as a product of a constant matrix (stoichiometric matrix) and its kinetics. Such special feature enables us to utilize the existing results from linear algebra to identify network conditions for addressing questions about dynamics. In this thesis, we reviewed some results by M. Feignberg and his collaborators regarding to the graphic conditions for multiplicity of equilibria (constant solutions), and also reviewed a result by Hirono et …

Friedel-Crafts Alkylation Of Benzene With A Superacid Catalyst, Josh T. Cutright

Undergraduate Honors Theses

Long-chain alkylbenzenes are industrially synthesized precursors to commercial surfactants such as laundry detergent. The currently used catalysts in the processes of their synthesis are corrosive and harmful to the environment. These problems can be avoided utilizing heterogeneous highly acidic catalysts. Solid catalysts do not corrode equipment and are relatively simple to remove from the post-reaction mixture. Phosphotungstic acid (PTA) supported on silica gel could be a possible catalyst due to its high acidity with an estimated pKa ≈ -13. The catalyst PTA-SiO₂ was prepared via the sol-gel method to covalently embed it in a silica support. The catalyst was …

Nitrogen Doping Of Electrochemically Activate Carbon Screen-Printed Electrodes, Ethan Galloway

Undergraduate Honors Theses

Screen printed electrodes (SPEs), which are prepared by patterning conductive inks or pastes onto an insulating support (e.g., plastic film), are widely employed as sensing and biosensing platforms due to their ease of fabrication and relatively low cost. This is especially applicable to electrodes of this nature prepared with carbon-based inks (SPCEs). To date, the most successful and significant commercial application of SPEs has been as test strips for glucose meters. Despite the maturity of this technology, SPE research remains very active as improvements in sensitivity and selectivity, which often involve modifying the electrode surface, hold the key to advancing …

Extraction And Partial Purification Of An Antibiotic-Like Compound From The Soil Bacterium Rhodococcus Strain Kchxc3, Elizabeth Bond

Undergraduate Honors Theses

Rhodococcus bacteria have many secondary metabolic pathways that may produce novel natural products. The bacterium Rhodococcus strain KCHXC3 was isolated from a soil sample collected near Kingsport, Tennessee and was found to produce an inhibitory compound active against a broad array of bacterial species, including the Gram negative pathogen Shigella sonnei. The aim of this research is to extract and purify the compound for future structure elucidation. A mixture of compounds from 3 month old agar plates inoculated with strain KCHXC3 was extracted using ethyl acetate. The crude extract was then partially purified utilizing a Sephadex LH-20 column, followed …

Synthesis And Function Of Ion-Selective Single-Molecule Fluorescent Imaging Molecules And Materials, Alena A. Denisenko

Chemistry & Biochemistry Dissertations - Archive

Neutrinos are fermion subatomic particles that interact only by weak subatomic forces—making them almost impossible to detect. However, they can be produced in specific radioactive decay reactions, such as beta decay. We hypothesize the detection of double beta decay through the tagging of the Ba2+ daughter ion from 136Xe (136Xe —136Ba2+ + 2ν + 2β). The proposal is to develop single-molecule fluorescence imaging (SFMI) technology to investigate gaseous chemical constituents in high-pressure gases (ca. 30-150 psi) at gas-solid interfaces. To achieve proper SMFI, heterogenous self-assembled monolayers (SAMs) containing fluorophores that operate under dry conditions and are turned on when a …

The Design Of A Efficient Production And Purification Of Fibroblast Growth Factor 2, Mandeep Kaur

Chemistry & Biochemistry Undergraduate Honors Theses

Chronic wounds pose a major problem in the United States with an estimate of twenty-five million dollars a year spent on associated treatments. Growth factors can be used as a potential treatment for chronic wounds since they promote cell proliferation and angiogenesis. This study employs one specific growth factor, fibroblast growth factor 2 (FGF2) so that it could potentially be used in future treatment. Wild-type FGF2 is thermally unstable, and it has a mean elimination time of 7.6 hours. This study attempted to improve upon its stability through a mutation on the heparin binding loop. The mutation performed was K134E. …

Design & Analysis Of Mixed-Mode Integrated Circuit For Pulse-Shape Discrimination, Bryan Orabutt

McKelvey School of Engineering Graduate Student Theses & Dissertations

In nuclear science experiments it is usually necessary to determine the type of radiation, its energy and direction with considerable accuracy. The detection of neutrons and discriminating them from gamma rays is particularly difficult. A popular method of doing so is to measure characteristics intrinsic to the pulse shape of each radiation type in order to perform pulse-shape discrimination (PSD).

Historically, PSD capable systems have been designed with two approaches in mind: specialized analog circuitry, or digital signal processing (DSP). In this work we propose a PSD capable circuit topology using techniques from both the analog and DSP domains. We …

Liquid Chromatography With Tandem Mass Spectrometry Method Development For The Determination Of Β–Defensins In Bovine Milk, Symone T. Whalin

Masters Theses & Specialist Projects

Bovine mastitis, caused by a wide array of pathogens, results in a substantial economic loss for the dairy cattle livestock industry. β-defensins are a part of the bovine’s innate immune system and act as the first line of defense against mastitis. Only foundational research has been done on β-defensins’ ability to treat and prevent mastitis. There have been no analytical methods reported in the literature for analyzing β-defensins in bovine milk. This research aims to create an analytical approach to determine β-defensins in bovine milk. It is challenging to determine an analyte in a complex sample matrix, and milk is …

Investigation Of The Cellular Uptake And Cytotoxicity Of Ruthenium(Ii) Polypyridyl Complexes As A Function Of Lipophilicity, Matthew Guerrero

Chemistry & Biochemistry Theses - Archive

Ru(II) polypyridyl complexes have been one of the focal points of investigation for inorganic anti-cancer drugs, as they are robust enough to remain chemically intact in vivo and many show potent cytotoxicty. In particular, the RPC [Ru(dip)3]2+, where dip is 4,7-diphenyl-1,10-phenanthroline, is noted for its high cytotoxicity (IC50 ~2-5 uM) across a broad spectrum of cancer cell lines and more recently has been implicated as targeting microtubules, which is an unusual target for metal-based drugs. While the cellular uptake for [Ru(dip)3]Cl2 is among the highest seen for RPCs, its solubility in water or buffer is limited and problematic. In order …

Investigation Of F420-Dependent Glucose-6-Phosphate Dehydrogenase Variants Using Ph Profiles And Stopped-Flow Spectrometric Ligand-Binding Methods, Ana Laura Alvarez

Chemistry & Biochemistry Theses - Archive

F420-dependent glucose-6-phosphate dehydrogenase (FGD) from Mycobacteria tuberculosis, catalyzes a reaction the conversion of glucose-6-phosphate (G6P) to 6-phosphogluconolactone using the oxidized F420 cofactor, which is reduced to F420H2. The reaction is important within M. tuberculosis, the cause of tuberculosis disease (TB) due to its health relevance for treatment of multiple drug resistant and extreme drug resistant strains of M. tuberculosis. TB affects millions of people worldwide, and although treatable, multiple drug resistant and extreme drug resistant forms of TB adds strain on the current generation of drugs. Since this enzyme is not found in humans, is an ideal drug target. A …